Radiation imaging device and radiation imaging system

Abstract

To provide a technique advantageous for improving detection accuracy of irradiation information.SOLUTION: A radiation imaging device includes a driving circuit, and a detection circuit for detecting radiation irradiation information on the basis of a signal read from pixels via signal lines, where the signal lines are respectively connected to pixels arranged in two pixel columns adjacent to each other, a first pixel and a second pixel having lower sensitivity to radiation than the first pixel are connected to a same signal line, and a third pixel and a fourth pixel are connected to a same signal line. When detecting the irradiation information, the drive circuit drives the first pixel and the second pixel at different timings from each other and drives the third pixel and the fourth pixel at different timings from each other. The detection circuit detects the irradiation information based on information regarding an irradiation amount corresponding to signals output from the first pixel and the second pixel, and information regarding a correction amount corresponding to signals output from the third pixel and the fourth pixel.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a radiation imaging device and a radiation imaging system.

Background Art

[0002] A radiation imaging device including a sensor substrate in which a plurality of pixels that convert incident radiation into an electrical signal are arranged in a two-dimensional matrix, and a drive circuit and a readout circuit for driving the pixels arranged on the sensor substrate and reading out signals is widely used. The readout circuit is expensive because analog amplifiers, analog / digital (A / D) converters, etc. are integrated at high density, and occupies a large proportion of the component cost of the radiation imaging device. Patent Document 1 shows that signal lines for outputting signals in two adjacent pixel columns are shared to reduce the circuit scale of the readout circuit connected to the signal lines.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As a multifunctionalization of a radiation imaging device, by detecting irradiation information of radiation incident on the radiation imaging device, detecting the start or end of radiation irradiation, detecting the incident radiation dose, and performing automatic exposure control (AEC) can be mentioned. Even in a radiation imaging device that shares signal lines in two adjacent pixel columns, in order to detect radiation irradiation and radiation dose with high accuracy, it is necessary to detect radiation irradiation information with high accuracy.

[0005] An object of the present invention is to provide a technique advantageous for improving the detection accuracy of irradiation information.

Means for Solving the Problems

[0006] In view of the above problems, a radiation imaging apparatus according to an embodiment of the present invention includes a plurality of pixels arranged to form a plurality of rows and a plurality of columns, a driving circuit that controls the plurality of pixels via a plurality of driving lines extending in a row direction, and a detection circuit that detects irradiation information of radiation separately from a radiation image based on signals read out from the plurality of pixels via a plurality of signal lines. In the radiation imaging apparatus, each of the plurality of signal lines is connected to pixels arranged in two pixel columns adjacent to each other in the row direction among the plurality of pixels. The plurality of pixels include a first pixel, a second pixel, a third pixel, and a fourth pixel. The first pixel and the second pixel having lower sensitivity to radiation than the first pixel are connected to the same signal line among the plurality of signal lines and are respectively connected to different driving lines among the plurality of driving lines. The third pixel and the fourth pixel are connected to the same signal line among the plurality of signal lines and are respectively connected to different driving lines among the plurality of driving lines. When detecting the irradiation information, the driving circuit drives the first pixel and the second pixel at different timings, and drives the third pixel and the fourth pixel at different timings. The detection circuit detects the irradiation information based on information regarding an irradiation amount corresponding to a first signal output from the first pixel and a second signal output from the second pixel, and information regarding a correction amount corresponding to a third signal output from the third pixel and a fourth signal output from the fourth pixel.

Advantages of the Invention

[0007] According to the present invention, it is possible to provide a technique advantageous for improving the detection accuracy of irradiation information.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims. Although a plurality of features are described in the embodiments, not all of these plurality of features are essential to the invention, and the plurality of features may be arbitrarily combined. Further, in the accompanying drawings, the same or similar configurations are denoted by the same reference numerals, and redundant descriptions are omitted.

[0010] In addition, the radiation in the present disclosure is a beam formed by particles (including photons) emitted by radioactive decay, such as α-rays, β-rays, γ-rays, and also includes beams having energy equal to or higher than that, for example, X-rays, particle beams, cosmic rays, and the like.

[0011] With reference to FIGS. 1(a), 1(b) to 6, a radiation imaging apparatus according to an embodiment of the present disclosure will be described. The following embodiments are all examples of the present disclosure and do not limit the invention according to the claims. FIG. 1(a) is an equivalent circuit diagram showing a configuration example of a radiation imaging apparatus 100 according to a part of the embodiments of the present disclosure. The radiation imaging apparatus 100 may include a plurality of pixels 1 arranged to form a plurality of rows and a plurality of columns, a driving circuit 10, a reading circuit 12, a detection circuit 13, and a power supply circuit 11. Hereinafter, when indicating a specific pixel among the plurality of pixels 1 arranged in the radiation imaging apparatus 100, a subscript is added after the reference numeral, such as pixel 1 "a". When not particularly distinguished, it is simply denoted as "pixel 1". The same applies to other components.

[0012] The drive circuit 10 controls a plurality of pixels 1 via a plurality of drive lines 6 extending in the row direction (the horizontal direction in FIG. 1(a)). The drive circuit 10 includes, for example, a shift circuit, and outputs signals from each of the plurality of pixels 1 in order via the plurality of drive lines 6 in response to a start signal, a clock signal, etc. transferred from a control circuit (not shown).

[0013] The readout circuit 12 reads out the signals generated by the plurality of pixels 1 via a plurality of signal lines 3. More specifically, the signal of the pixel 1 driven via the drive line 6 by the drive circuit 10 is read out by the readout circuit 12. The readout circuit 12 may include an amplifier circuit 9, a multiplexer MUX, an analog-to-digital conversion circuit ADC, etc. The readout circuit 12 performs analog-to-digital (AD) conversion on the signal generated by the pixel 1, and transfers digital signals corresponding to the analog signals generated by the pixel 1 to the detection circuit 13 in order. In the present embodiment, each of the plurality of signal lines 3 is connected to the pixels 1 arranged in two pixel columns adjacent to each other in the row direction among the plurality of pixels 1. By sharing one signal line 3 by two pixel columns, the number of amplifier circuits 9 and the circuit scale of the multiplexer MUX of the readout circuit 12 are suppressed. As a result, in the radiation imaging apparatus 100, the circuit scale of the readout circuit 12 can be suppressed.

[0014] The detection circuit 13 detects radiation irradiation information separately from the radiation image based on the signals read out from the plurality of pixels 1 via the plurality of signal lines 3 by the readout circuit 12. Here, the radiation irradiation information separate from the radiation image may be information on the start or end of radiation irradiation, information on the dose of incident radiation, etc. By the detection circuit 13 detecting the radiation irradiation information, the radiation imaging apparatus 100 can incorporate an automatic exposure control (AEC) function.

[0015] The detection of the irradiation information can be performed, for example, by the arithmetic circuit 2 included in the detection circuit 13. The arithmetic circuit 2 may be configured to include a processor such as a CPU. The operation of the detection circuit 13 can be executed by the processor of the arithmetic circuit 2 executing a program stored in the storage circuit 7 using a RAM, a ROM, or the like. Further, the arithmetic circuit 2 may be configured by a dedicated circuit such as an application specific integrated circuit (ASIC). Furthermore, the detection circuit 13 may generate radiation image data based on signals output from the plurality of pixels 1. The radiation image data is transferred to a monitor or the like located outside the radiation imaging apparatus 100, and an image generated using the radiation image data can be displayed on the monitor as the captured radiation image.

[0016] The power supply circuit 11 supplies power to each component such as the drive circuit 10, the readout circuit 12, and the detection circuit 13 in the radiation imaging apparatus 100. Further, the power supply circuit 11 supplies a bias voltage for converting the incident radiation into a charge signal by the pixel 1 to the pixel 1 via the bias line 8.

[0017] In the configuration shown in FIG. 1(a), pixels 1 of 4 rows × 6 columns are shown. However, the arrangement of the pixels 1 is not limited to this, and a larger number of pixels 1 can be arranged in the radiation imaging apparatus 100. For example, in a radiation imaging apparatus 100 with a pixel area where the pixels 1 are arranged having a size of 17 inches, about 2800 rows × about 2800 columns of pixels 1 can be arranged in the pixel area.

[0018] The plurality of pixels 1 include pixels 1a, 1b, 1c, and 1d that are used by the detection circuit 13 to detect irradiation information of radiation separately from the radiation image. The pixel 1b has lower sensitivity to radiation than the pixel 1a. The pixel 1a and the pixel 1b are connected to the same signal line 3 (signal line 3a) among the plurality of signal lines 3, and are respectively connected to different drive lines 6 (pixel 1a: drive line 6a, pixel 1b: drive line 6b) among the plurality of drive lines 6.

[0019] Pixel 1c and pixel 1d are connected to the same signal line 3 (signal line 3b) among the plurality of signal lines 3, and are respectively connected to different driving lines 6 (pixel 1c: driving line 6a, pixel 1d: driving line 6b) among the plurality of driving lines 6. The sensitivities of pixel 1c and pixel 1d to radiation are substantially the same. That the sensitivities to radiation are substantially the same may mean, for example, that the difference in sensitivities is ±10% or less. Also, that the sensitivities to radiation are substantially the same may mean that they have the same sensitivity. Although the structure will be described later, it can also be said that pixel 1c and pixel 1d do not have a structural configuration that causes a difference in the sensitivity to radiation.

[0020] Also, pixel 1a may have a higher sensitivity to radiation than pixel 1c and pixel 1d. In that case, the sensitivities of pixel 1b and pixel 1c and pixel 1d to radiation may be substantially the same.

[0021] Although details will be described later, based on the signal output from pixel 1a and the signal output from pixel 1a, information regarding the irradiation amount of the radiation incident on the radiation imaging device 100 is obtained. Also, based on the signal output from pixel 1c and the signal output from pixel 1d, information regarding the correction amount is obtained. The detection circuit 13 detects irradiation information of radiation different from the radiation image, such as the start or end of radiation irradiation and information on the dose of the incident radiation, for example, to perform AEC, based on the information regarding the irradiation amount and the method regarding the correction amount.

[0022] As shown in FIG. 1(a), each pixel 1 includes a conversion element 20 for converting radiation into charge, and a switch element 21 for outputting a signal corresponding to the converted charge to the signal line 3. The signal line 3 can be arranged in the vicinity of the conversion element 20 of the pixel 1. For this reason, a non-negligible parasitic capacitance is formed between the signal line 3 and the electrode of the conversion element 20, and crosstalk occurs in which the charge of the conversion element 20 of the pixel 1 is transmitted to the signal line 3 through the parasitic capacitance.

[0023] When detecting irradiation information, since pixel 1a and pixel 1b are connected to the same signal line 3a, they are driven by the driving circuit 10 at different timings. In that case, when reading a signal for obtaining irradiation information from pixel 1a, charges are accumulated in the electrodes of the conversion element 20 of pixel 1 by the incident radiation, and a signal caused by crosstalk is transmitted to the signal line 3a through the parasitic capacitance. Similarly, when reading a signal for obtaining irradiation information from pixel 1b, a signal caused by crosstalk is transmitted to the signal line 3a through the parasitic capacitance. Since these two signals caused by crosstalk are signals for the same signal line 3a, they can be approximately the same amount. Therefore, by taking the difference between the signal output from pixel 1a and the signal output from pixel 1b, it becomes possible to suppress the component caused by crosstalk of the signal output from pixel 1a. That is, the accuracy of the detection circuit 13 for detecting irradiation information is improved. As a result, in the radiation imaging apparatus 100, the accuracy of functions implemented using irradiation information such as AEC is improved.

[0024] Also, the signal read from pixel 1 may include an offset component caused by each element such as a transistor arranged in the amplification circuit 9 or the like in the readout circuit 12. This offset component may change in characteristics depending on the temperature change during the driving of the radiation imaging apparatus 100 or the environment in which it is used. On the other hand, pixel 1a and pixel 1b used when the detection circuit 13 detects irradiation information read signals from the same signal line 3a. Therefore, by taking the difference between the signal output from pixel 1a and the signal output from pixel 1b, the influence of the offset component caused by transistors or the like arranged in the amplification circuit 9 or the like can be suppressed. Therefore, the accuracy of the detection circuit 13 for detecting irradiation information used for the AEC function is improved. As a result, in the radiation imaging apparatus 100, the accuracy of functions implemented using irradiation information such as AEC is improved.

[0025] On the other hand, there may be a difference in signal components between pixel 1a and pixel 1b due to the positions where pixels 1a and 1b are respectively arranged or being driven at different timings. When detecting irradiation information, if the difference between the signal output from pixel 1a and the signal output from pixel 1b is used, this difference will include the difference in signal components caused by the positions and driving timings of pixels 1a and 1b.

[0026] Therefore, in the present embodiment, information regarding a correction amount for correcting the difference in signal components caused by the positions and driving timings where pixels 1a and 1b are arranged is obtained by using the signals output from pixel 1c and the signal output from pixel 1d. That is, the difference a between the signal output from pixel 1a and the signal output from pixel 1b and the difference b between the signal output from pixel 1c and the signal output from pixel 1d are used to detect irradiation information based on the difference a and the difference b. Thereby, it becomes possible to suppress the difference in signal components caused by the positions and driving timings where pixels 1a and 1b are arranged. As a result, the accuracy of the detection circuit 13 for detecting irradiation information is further improved, and in the radiation imaging apparatus 100, the accuracy of functions implemented using irradiation information such as AEC is improved.

[0027] In the configuration shown in FIG. 1(a), two pixels 1 that are adjacent to each other in the row direction among a plurality of pixels 1 and are connected to a common signal line 3 have a point-symmetric configuration with the common signal line 3 interposed therebetween (details are shown in FIG. 3(a)). The axis of symmetry may be, for example, the intersection of the line connecting the geometric center-of-gravity positions of the electrodes (for example, electrode 111 or electrode 115 described later) provided in the conversion elements 20 of the two pixels 1 and the center line in the column direction (vertical direction in FIG. 1(a)) of the signal line 3. In the present embodiment, as shown in FIG. 1(a), the pixels 1a and 1b for detecting irradiation information are arranged in the same row and have a point-symmetric relationship with the common signal line 3a interposed therebetween. Therefore, when an alignment deviation or the like occurs during the fabrication of the switch element 21, an offset component (for example, one signal increases and the other signal decreases) due to the alignment deviation may occur between the signal output from the pixel 1a and the signal output from the pixel 1b.

[0028] On the other hand, the pixels 1c and 1d for detecting irradiation information together with the pixels 1a and 1b are also arranged in the same row and have a point-symmetric relationship with the common signal line 3b interposed therebetween. In other words, the positional relationship in the row direction and the column direction in which the pixel 1b is arranged with respect to the pixel 1a is the same as the positional relationship in the row direction and the column direction in which the pixel 1d is arranged with respect to the pixel 1c. In the configuration shown in FIG. 1(a), the pixels 1a, 1b, 1c, and 1d are arranged in the same pixel row. Therefore, even when an offset component due to the alignment deviation between the signal output from the pixel 1a and the signal output from the pixel 1b occurs, an offset component due to the same alignment deviation may also occur between the signal output from the pixel 1c and the signal output from the pixel 1d. Therefore, by using the signals output from the pixels 1c and 1d, it is possible to suppress the difference in the signal components due to the positions where the pixels 1a and 1b are arranged. Further, such an offset component due to the alignment deviation can be further reduced by previously storing in a memory circuit 7 or the like the data of the offset components between the pixels 1a and 1b and between the pixels 1c and 1d obtained without irradiating radiation.

[0029] Also, when detecting the irradiation information, by the driving circuit 10, the pixel 1a and the pixel 1c connected to the same driving line 6a are driven at the same timing, and the pixel 1b and the pixel 1d connected to the same driving line 6b are driven at the same timing. The timing at which signals are read out from the pixel 1a and the pixel 1b is different. It was described above that the signals caused by crosstalk are substantially the same amount for the signals on the same signal line 3a. However, between the signal output from the pixel 1a and the signal output from the pixel 1b, for example, as charge is accumulated in the pixel 1, the amount of crosstalk with respect to the signal line 3 may change. Even in that case, a signal is read out from the pixel 1c at the same timing as the pixel 1a, and a signal is read out from the pixel 1d at the same timing as the pixel 1b. Thereby, it becomes possible to suppress the difference in the signal components due to the driving timing of the pixels 1a and 1b.

[0030] Thus, by using the pixels 1a to 1d, the accuracy with which the detection circuit 13 detects the irradiation information is improved. As a result, in the radiation imaging apparatus 100, the accuracy of functions implemented using irradiation information such as AEC is improved.

[0031] The pixels 1a and 1b for detecting the irradiation information of radiation separately from the radiation image do not necessarily have to be adjacent to each other in the row direction as long as they are connected to the same signal line 3. For example, as shown in FIG. 1(b), the pixels 1a and 1b may be arranged in the same pixel column. Similarly, the pixels 1c and 1d do not necessarily have to be adjacent to each other in the row direction as long as they are connected to the same signal line 3b. On the other hand, as shown in FIG. 1(b), similar to the positional relationship between the pixels 1a and 1b, the pixels 1c and 1d can also be arranged in the same pixel column. That is, similar to the arrangement shown in FIG. 1(a), the pixels 1a to 1d are arranged so that the positional relationship in which the pixel 1b is arranged with respect to the pixel 1a and the positional relationship in which the pixel 1d is arranged with respect to the pixel 1c are the same relationship. Thereby, the accuracy of the information regarding the correction amount corresponding to the signal output from the pixel 1c and the signal output from the pixel 1d can be improved.

[0032] When having the configuration shown in FIG. 1(b), compared with the case where the pixel 1a and the pixel 1b shown in FIG. 1(a) have a point-symmetrical configuration, the offset component caused by the alignment deviation in the row direction between the pixel 1a and the pixel 1b can be substantially the same. Therefore, by simply obtaining the difference between the signal output from the pixel 1a and the signal output from the pixel 1b, the influence of the offset component caused by the alignment deviation in the row direction can be further suppressed. Here, also in the configuration shown in FIG. 1(a) and also in the configuration shown in FIG. 1(b), the alignment deviation in the column direction is substantially the same. Therefore, regarding the alignment deviation in the column direction, between the pixel 1a and the pixel 1b (and between the pixel 1c and the pixel 1d), it is difficult for an offset component caused by the alignment deviation in the column direction to occur between the output signals.

[0033] Also, for example, as shown in FIG. 2(a), pixel 1a, pixel 1b, pixel 1c, and pixel 1d may be arranged in different pixel rows and different pixel columns from each other. Even in that case, each of the pixels 1a to 1d can be arranged so that the relative positional relationship in which pixel 1b is arranged with respect to pixel 1a and the relative positional relationship in which pixel 1d is arranged with respect to pixel 1c are the same relationship. Thereby, even when there is an alignment deviation in the row direction and the column direction, the offset component caused by the alignment deviation in the row direction and the column direction can be corrected by using the signals output from pixel 1c and pixel 1d. Also, as shown in FIG. 2(b), pixel 1a, pixel 1b, pixel 1c, and pixel 1d may be arranged in the same pixel column and connected to the same signal line 3a. Thereby, similar to the relationship between the configuration shown in FIG. 1(a) and the configuration shown in FIG. 1(b), the influence of the offset component caused by the alignment deviation in the row direction can be suppressed. Also, in the configuration shown in FIG. 2(b), each of the pixels 1a to 1d may be arranged so that the relative positional relationship in which pixel 1b is arranged with respect to pixel 1a and the relative positional relationship in which pixel 1d is arranged with respect to pixel 1c are the same relationship. In the configuration shown in FIG. 2(b), in the column direction, they are arranged in the order of pixel 1a, pixel 1c, pixel 1b, pixel 1d. One pixel row in which pixel 1c is arranged is arranged between pixel 1a and pixel 1b, and one pixel row in which pixel 1b is arranged is arranged between pixel 1c and pixel 1d. However, it is not limited to this. For example, in the column direction, in the order of pixel 1a, pixel 1b, pixel 1c, pixel 1d, pixel 1a and pixel 1b may be arranged in adjacent pixel rows to each other, and pixel 1c and pixel 1d may be arranged in adjacent pixel rows to each other.

[0034] Here, as shown in FIGS. 2(a) and 2(b), consider the case where pixels 1a to 1d are connected to different driving lines 6a to 6d, respectively. In that case, in the configuration shown in FIG. 2(a), for example, the driving circuit 10 may drive pixel 1a and pixel 1c at the same timing via driving lines 6a and 6c, and similarly, drive pixel 1b and pixel 1d at the same timing via driving lines 6b and 6d. Also, in the configuration shown in FIG. 2(b), when pixel 1a and 1c are driven at the same timing, the signals output from pixel 1a and pixel 1c will overlap, so pixel 1a and pixel 1c cannot be driven at the same timing. Similarly, pixel 1b and pixel 1d cannot be driven at the same timing. Therefore, in order to suppress the difference in signal components caused by the driving timing as described above, when detecting the irradiation information, the driving circuit 10 makes the time difference between the timing of driving pixel 1a and the timing of driving pixel 1b, and the time difference between the timing of driving pixel 1c and the timing of driving pixel 1d, the same, and may drive each of pixel 1a, pixel 1b, pixel 1c, and pixel 1d. Thereby, for example, even when the amount of crosstalk changes according to the charge accumulation state of pixel 1 over time, the offset component caused by the amount of crosstalk can be suppressed.

[0035] The arrangement of pixels 1a, 1b, 1c, and 1d for detecting such irradiation information is not limited to the above-described present embodiment, and the number and positions of pixels 1a, 1b, 1c, and 1d may be changed as appropriate. For example, a combination of pixels 1a, 1b, 1c, and 1d may be arranged at regular intervals in a specific row. Further, as described above, the accuracy of detecting irradiation information is improved when the positional relationship in the row direction and the column direction in which pixel 1b is arranged with respect to pixel 1a and the positional relationship in the row direction and the column direction in which pixel 1d is arranged with respect to pixel 1c are the same relationship. However, it is not limited thereto. Pixel 1a and pixel 1b are connected to the same signal line 3 and are connected to different driving lines 6 from each other. Further, if pixel 1c and pixel 1d are connected to the same signal line 3 and are connected to different driving lines 6 from each other, pixels 1a to 1d may be arranged at appropriate positions, respectively.

[0036] The pixel row in which pixels 1a, 1b, 1c, and 1d are arranged (hereinafter may be referred to as the AEC row) has fewer pixels 1 used for the radiation image compared to other pixel rows. When generating a radiation image, the image signal corresponding to the signals output from pixels 1a, 1b, 1c, and 1d needs to be corrected or interpolated using the output values of pixels 1 around the AEC row. Also, the pixels 1 arranged in the AEC row have their signals repeatedly read during radiation irradiation together with pixels 1a, 1b, 1c, and 1d. Therefore, for the pixels 1 arranged in the AEC row, correction or interpolation may be required using the output values of pixels 1 around the AEC row. That is, a radiation image may be generated based on the signals output from the pixels 1 arranged outside the pixel row in which pixels 1a, 1b, 1c, and 1d are arranged among the plurality of pixels 1 arranged in the radiation imaging apparatus 100. In the configuration shown in FIG. 1(a), corresponding to the arrangement of pixels 1a to 1d, there is 1 AEC row, whereas in the configuration shown in FIG. 1(b), there are 2 AEC rows, and in the configurations shown in FIGS. 2(a) and 2(b), there are 4 AEC rows. Therefore, in the configuration shown in FIG. 1(a), since there is 1 AEC row that requires correction or interpolation, the correction accuracy when generating a radiation image can be higher than that in the configurations shown in FIGS. 1(b), 2(a), and 2(b).

[0037] Also, in the configuration shown in FIG. 1(a), pixel 1a and pixel 1b are arranged adjacent to each other, and similarly, pixel 1c and pixel 1d are arranged adjacent to each other. Therefore, the dose of incident radiation can be substantially the same. Thus, the difference due to the different drive timings of the amount of crosstalk superimposed on the signals output from pixel 1a and pixel 1b, and pixel 1c and pixel 1d, respectively, can be equivalent. Therefore, the offset component caused by crosstalk can be accurately suppressed. Also, for example, in the arrangements shown in FIGS. 1(b), 2(a), and 2(b), the pixel rows arranged between the pixel row in which pixel 1a is arranged and the pixel row in which pixel 1b is arranged may be 10 rows or less, or may be 5 rows or less. Further, pixel 1a and pixel 1b may be arranged in adjacent rows. The arrangement of pixel 1c and pixel 1d may be the same as the positional relationship between pixel 1a and pixel 1b.

[0038] FIG. 3(a) is a plan view showing a configuration example of pixel 1a and pixel 1b in the present embodiment. FIGS. 3(b) and 3(c) are cross-sectional views taken along A-A' and B-B' shown in FIG. 2(a), respectively. Pixels other than pixel 1a to 1d among the plurality of pixels 1 may have the same structure as pixel 1a. In the configuration shown in FIG. 3(a), two pixels 1a and 1b that are adjacent to each other in the row direction and connected to a common signal line 3a have a point-symmetric configuration with the signal line 3a in between. However, it is not limited to this. For example, pixels 1a and 1b may have a line-symmetric configuration with the common signal line 3a in between. In order to make pixels 1a and 1b in a line-symmetric relationship, for example, the switch element 21 may be arranged at the center in the column direction. The same applies to other pixels 1 that are adjacent to each other in the row direction and connected to the same signal line 3. When pixels 1a and 1b have a line-symmetric configuration, the axis of symmetry may be, for example, the center line in the column direction of signal line 3.

[0039] In this embodiment, above the cross-sectional views of FIGS. 3(b) and 3(c), a scintillator (not shown) that generates light corresponding to the incident radiation is provided. The scintillator is arranged to cover a plurality of pixels 1. The light converted by the scintillator is converted into electric charges by a conversion element 20 and transferred to a signal line 3 via a switch element 21. That is, the pixel 1 of this embodiment is an indirect-type element including a scintillator that converts radiation into light detectable by the conversion element 20, but a direct-type conversion element 20 that directly converts radiation into electric charges may be used for the pixel 1. When the direct-type conversion element 20 is used, the scintillator may not be arranged.

[0040] As shown in FIGS. 3(a) to 3(c), a conversion element 20 and a switch element 21 are arranged in the pixels 1a and 1b. Also, wiring patterns such as a signal line 3a, drive lines 6a and 6b, and a bias line 8 connected to the pixels 1a and 1b are arranged. In this embodiment, a pin diode is used as the conversion element 20, and the conversion element 20 includes an electrode 111, an impurity semiconductor layer 112, a semiconductor layer 113, an impurity semiconductor layer 114, an electrode 115, and a protective layer 116. In this embodiment, a thin film transistor (TFT) is used as the switch element 21, and the switch element 21 includes a control electrode 101, a main electrode 105 (source electrode in this embodiment), a main electrode 106 (drain electrode in this embodiment), an insulating layer 102, a semiconductor layer 103, and an impurity semiconductor layer 104.

[0041] The upper electrode (electrode 115) of the conversion element 20 is connected to a bias line 8 for applying a constant bias voltage. The electrode 111 of the conversion element 20 is connected to the main electrode 106 of the switch element 21. The control electrode 101 of the switch element 21 is connected to the drive lines 6a and 6b, and the conduction state / non-conduction state of the switch element 21 is controlled by signals supplied from a drive circuit 10 to the drive lines 6a and 6b. The main electrode 105 of the switch element 21 is connected to the signal line 3a, and when the switch element 21 is in a conduction state, the electric charges of the conversion element 20 are transferred to the signal line 3a as an electric signal.

[0042] The difference between pixel 1a and pixel 1b shown in FIGS. 3(a) to 3(c) is that the light shielding layer 22 is not provided in pixel 1a, while the light shielding layer 22 is provided in pixel 1b. The light shielding layer 22 may be formed using the bias line 8 as shown in FIG. 3(c). The light shielding layer 22 has a role of shielding the light converted from radiation by the scintillator to which the conversion element 20 is sensitive. Therefore, the light shielding layer 22 is provided between pixel 1b and the scintillator. When the bias line 8 is formed of a metal or the like that shields the light generated by the scintillator, the width of the bias line 8 may be widened to cover the entire surface of the conversion element 20 of pixel 1b. Thereby, pixel 1b having a lower sensitivity to radiation than pixel 1a can be formed without increasing the number of processes in manufacturing the radiation imaging apparatus 100. Covering the entire surface of the conversion element 20 in pixel 1b is for suppressing leakage light. However, the present invention is not limited to this, and any configuration may be used as long as the sensitivity to radiation is different between pixel 1a and pixel 1b. For example, the light shielding layer 22 may be formed using a metal layer different from the bias line 8, or a part of the conversion element 20 of pixel 1b may not be covered by the light shielding layer 22. Further, for example, a colored (e.g., black) resin as a light shielding layer may be disposed between the protective layer 116 and the scintillator so as to cover the conversion element 20 of pixel 1b. When the conversion element 20 is a direct type conversion element, the conversion element 20 of pixel 1b may be covered with a shielding member using lead, tungsten, or the like so that radiation is less likely to enter the conversion element 20 of pixel 1b. For example, the electrode 115 of the conversion element 20 disposed in pixel 1b may be formed of lead or tungsten.

[0043] If the sensitivities of pixel 1c and pixel 1d to radiation are substantially the same, they may have a structure without the light-shielding layer 22 arranged like pixel 1a, or may have a structure with the light-shielding layer 22 arranged like pixel 1b. As described above, pixel 1c and pixel 1d only need to have a structure that does not cause a difference in sensitivity to radiation structurally (there may be a slight difference in sensitivity to radiation due to manufacturing process errors, etc.). Also, when pixel 1c and pixel 1d are covered by the light-shielding layer 22, the light-shielding layer 22 does not necessarily cover the entire conversion element 20. Also, AEC or the like using irradiation information can be carried out by arranging a subject between the radiation source and the radiation imaging apparatus 100. When a subject is arranged, depending on the configuration and the position where the subject is arranged, there may be a difference corresponding to the subject between the amount of radiation incident on pixel 1c and the amount of radiation incident on pixel 1d. Therefore, pixel 1c and pixel 1d may have the same configuration as pixel 1b with the light-shielding layer 22 arranged, whereby the influence caused by the arrangement of the subject can be suppressed.

[0044] In the above-described structure, a parasitic capacitance that is spatially mutually coupled is formed between the electrode 111 of the conversion element 20 and the signal line 3 (main electrode 105). Due to this parasitic capacitance, the electrode 111 of the conversion element 20 and the signal line 3 are capacitively coupled, and crosstalk occurs. The signal caused by this crosstalk is written from all the pixels 1 connected to the signal line 3, so it can become an enormous amount of signal. As a result, it may be difficult to correctly read out the signal output from pixel 1a connected to the signal line 3a. This crosstalk can be substantially the same on the same signal line 3. Therefore, by using the difference in signal output between pixel 1a and pixel 1b, crosstalk can be corrected with high precision, and information regarding the irradiation amount of radiation incident on the radiation imaging apparatus 100 can be obtained.

[0045] In addition, structural errors may occur in pixels 1a and 1b due to alignment errors or the like during the manufacture of pixel 1. This error causes a change in the parasitic capacitance of the pixel. This change causes a change in the offset component (the offset component caused by the alignment error) included in the signal output from pixels 1a and 1b. Due to the difference in this offset component, the detection accuracy of the radiation irradiation information deteriorates in the difference between the signal outputs of pixels 1a and 1b. Therefore, by using the difference between the signals output from pixels 1c and 1d as described above, it is possible to correct the difference in the offset components resulting from the structure such as the alignment error between pixels 1a and 1b. Also, as described above, it is possible to correct the offset component caused by the difference in the driving timing between pixels 1a and 1b. That is, with respect to the information regarding the above-described irradiation amount, it is possible to obtain information regarding the correction amount for correcting the information regarding the irradiation amount from the signals output from pixels 1c and 1d. Based on this information regarding the irradiation amount and the information regarding the correction amount, the radiation imaging apparatus 100 can detect the radiation irradiation information with high accuracy.

[0046] FIG. 4 is an example of a timing diagram showing the operation of the radiation imaging apparatus 100 when the detection circuit 13 detects radiation irradiation information used for an AEC function or the like separately from the radiation image. FIG. 4 is a timing diagram showing an example of the operation of the radiation imaging apparatus 100 having the configuration shown in FIGS. 1(a) and 1(b). "Vg1" indicates the signal Vg1 input to the drive line 6a for driving the pixels 1a and 1c. When the signal Vg1 is activated (H), the switch elements 21 of the pixels 1a and 1c are driven and become conductive, whereby signals are read out from the pixels 1a and 1c. "Vg2" indicates the signal Vg2 input to the drive line 6b for driving the pixels 1b and 1d. When the signal Vg2 is activated (H), the switch elements 21 of the pixels 1b and 1d are driven and become conductive, whereby signals are read out from the pixels 1b and 1d. "SH" indicates a sample hold operation, and when the signal SH is activated (H), the sample hold operation is performed. "RES" indicates a reset operation for resetting the charges accumulated in the signal line 3, each element arranged in the readout circuit 12, etc., and when the signal RES is activated (H), the reset operation is performed.

[0047] "Otput1", "Otput2", "Otput3", and "Otput4" represent the signals read out from pixel 1a, pixel 1b, pixel 1c, and pixel 1d, respectively, by the readout circuit 12 and transferred to the detection circuit 13. "Out1-Out2" on the signal line 3a is a signal indicating the difference (Output1-Output2) between the signal Output1 corresponding to the signal output from pixel 1a and the signal Output2 corresponding to the signal output from pixel 1b. "Out3-Out4" on the signal line 3b is a signal indicating the difference (Output3-Output4) between the signal Output3 corresponding to the signal output from pixel 1c and the signal Output4 corresponding to the signal output from pixel 1d. "Out" is the difference signal between "Out1-Out2" and "Out3-Out4". The signals Out1-Out2, Out3-Out4, and Out can be calculated, for example, by the arithmetic circuit 2 of the detection circuit 13 using the signals Output1 to 4. The detection circuit 13 detects radiation irradiation information from the signal Out. The method for calculating the signal Out is not limited to the above method as long as it is mathematically equivalent. For example, the difference between "Out1-Out3" and "Out2-Out4", the difference between "Out1+Out4" and "Out2+Out3", the sum of "Out1-Out2" and "Out4-Out3", etc. are equivalent to the difference between "Out1-Out2" and "Out3-Out4". As a result, equivalent signal Out can be obtained respectively.

[0048] Before the start of radiation irradiation, the drive circuit 10 sequentially activates the signal Vg1 and the signal Vg2 to drive the pixel 1a, the pixel 1b, the pixel 1c, and the pixel 1d. As a result, the detection circuit 13 can detect the start of radiation irradiation. The signals output by driving the pixel 1a, the pixel 1b, the pixel 1c, and the pixel 1d before the start of radiation irradiation include an offset component generated by a transistor or the like arranged in the readout circuit 12. When radiation is not being irradiated, in the signal Output1 and the signal Output2 corresponding to the signals output from the pixel 1a and the pixel 1b, when driven at the same timing, the offset components generated by a transistor or the like arranged in the readout circuit 12 can be approximately the same amount. Similarly, in the signal Output3 and the signal Output4 corresponding to the signals output from the pixel 1c and the pixel 1d, when driven at the same timing, the offset components generated by a transistor or the like arranged in the readout circuit 12 can be approximately the same amount.

[0049] However, since pixel 1a and pixel 1b are connected to the same signal line 3a, in order to output signal Output1 and signal Output2 respectively, it is necessary to drive pixel 1a and pixel 1b at different timings. Similarly, since pixel 1c and pixel 1d are connected to the same signal line 3b, in order to output signal Output3 and signal Output4 respectively, it is necessary to drive pixel 1c and pixel 1d at different timings. Driving pixel 1a and pixel 1b (pixel 1c and pixel 1d) at different timings may cause the offset component to change due to the time difference in driving, resulting in different outputs. For example, when driving pixel 1a and pixel 1c, the influence (noise) from pixel 1 driven before pixel 1a and pixel 1c can be superimposed on the signals output from pixel 1a and pixel 1c. Similarly, when driving pixel 1b and pixel 1d, the influence (noise) from pixel 1 (which may be a different pixel from the pixel 1 driven before pixel 1a and pixel 1c) driven before pixel 1b and pixel 1d can be superimposed on the signals output from pixel 1b and pixel 1d. The amount of noise superimposed on the signals output from pixel 1a and pixel 1c and the amount of noise superimposed on the signals output from pixel 1b and pixel 1d can be different from each other. That is, "Out1 - Out2" may include the difference in signal components due to the driving timings of pixel 1a and pixel 1b. Similarly, "Out3 - Out4" may include the difference in signal components due to the driving timings of pixel 1c and pixel 1d. Therefore, as the signal Out, the difference between "Out1 - Out2" and "Out3 - Out4" is taken. As a result, the signal Out can be made approximately zero as described above.

[0050] Next, when the irradiation of radiation is started, charges corresponding to the incident radiation are generated in pixel 1a. Here, it is assumed that pixels 1b, 1c, and 1d are shielded from light. During the irradiation of radiation, by sequentially activating signal Vg1 and signal Vg2 by drive circuit 10, readout circuit 12 sequentially transfers signals Output1, Output2, Output3, and Output4 corresponding to the signals read from pixels 1a, 1b, 1c, and 1d, respectively, to detection circuit 13. Detection circuit 13 acquires signal Out calculated from signals Output1, Output2, Output3, and Output4.

[0051] Here, the components included in signals Output1 to 4 are Output1 = R + Oa + Na ··· (1) Output2 = Oa + Nb ··· (2) Output3 = Ob + Nc ··· (3) Output4 = Ob + Nd ··· (4) Let it be so. Component R included in Output1 is a component corresponding to the incident radiation. Component Oa is a component corresponding to the offset component generated by transistors or the like arranged in amplifier circuit 9 provided in readout circuit 12 and connected to signal line 3a. Component Na is a component corresponding to the position where pixel 1a is arranged and the drive timing. Output2 includes component Oa similar to Output1 and component Nb corresponding to the position where pixel 1b is arranged and the drive timing. Output3 includes component Ob corresponding to the offset component generated by transistors or the like arranged in amplifier circuit 9 provided in readout circuit 12 and connected to signal line 3b and component Nc corresponding to the position where pixel 1c is arranged and the drive timing. Output4 includes component Ob similar to Output3 and component Nd corresponding to the position where pixel 1d is arranged and the drive timing.

[0052] As described above, signal Out can be obtained as (Output1 - Output2) - (Output3 - Output4). Therefore, from equations (1) to (4), Out = (Output1 - Output2) - (Output3 - Output4) = {(R + Oa + Na) - (Oa + Nb)} - {(Ob + Nc) - (Ob + Nd)} = {R + (Na - Nb)} - (Nc - Nd) ··· (5) It becomes as follows. Here, as described above, the difference in signal components due to the positions where pixels 1a and 1b are arranged and the driving timing, and the difference in signal components due to the positions where pixels 1c and 1d are arranged and the driving timing are substantially the same. That is, (Na - Nb) ≒ (Nc - Nd). Therefore, assuming (Na - Nb) = (Nc - Nd), Equation (5) becomes Out = {R + (Na - Nb)} - (Nc - Nd) = R As a result, from the signal Out, offset components, crosstalk, etc. caused by each element such as transistors arranged in the readout circuit 12, and signals caused by the positions where pixels 1a and 1b are arranged and the driving timing are suppressed, and the component R corresponding to the incident radiation remains. That is, the detection circuit 13 is based on the information on the irradiation amount obtained according to the signals output from pixels 1a and 1b (corresponding to {R + (Na - Nb)}), and the information on the correction amount obtained according to the signals output from pixels 1c and 1d (corresponding to (Nc - Nd)). It is possible to obtain radiation irradiation information with high accuracy from the signal Out. For example, the detection circuit 13 can detect the start of radiation irradiation with high accuracy from the result Out. Also, the dose of incident radiation can be read out with high accuracy from the signal Out, and the detection circuit 13 can also acquire the integrated dose with high accuracy. As a result, the radiation imaging apparatus 100 can perform AEC with high accuracy.

[0053] When pixel 1c and pixel 1d are not covered by the light shielding layer 22 or are partially covered by the light shielding layer 22, a component R’ corresponding to the incident radiation is added to Output3 and Output4 according to formulas (3) and (4), respectively. However, the component R’ can be canceled out during the calculation of (Output3 - Output4). Also, for example, information on the component R’ included in Output3 and Output4 respectively according to the radiation irradiation conditions set by the user may be stored in advance in a memory circuit 7 or the like, and correction may be performed during the calculation of (Output3 - Output4). Thereby, even when pixel 1c and pixel 1d are not covered by the light shielding layer 22, the detection circuit 13 can obtain radiation irradiation information from the signal Out with high accuracy.

[0054] For example, during radiation irradiation, when signals are read out from pixels 1a to 1d, signals caused by crosstalk generated in signal lines 3a and 3b are superimposed on the signals output from pixels 1a to 1d, respectively. However, the difference in the amount of crosstalk superimposed on the signals output from pixel 1a and pixel 1b and the difference in the amount of crosstalk superimposed on the signals output from pixel 1c and pixel 1d will be approximately the same if the time difference in the driving timing is approximately the same. By calculating the signal Out from the difference between signal Output1 and signal Output2 and the difference between signal Output3 and signal Output4, it becomes possible to suppress the influence of crosstalk superimposed on the read signal Out.

[0055] In the radiation imaging apparatus 100, after detecting the start of radiation irradiation or performing AEC or the like, the detection circuit 13 may stop controlling the detection of irradiation information. For example, when performing AEC, the radiation imaging apparatus 100 predicts the cumulative dose of radiation from the irradiation information detected by the detection circuit 13 and predicts the stop timing of the radiation. Next, when the radiation imaging apparatus 100 outputs information such as the predicted stop timing information and information indicating the stop of radiation irradiation to a control device that controls the radiation source, the detection circuit 13 may stop controlling the detection of irradiation information. Subsequently, in the drive circuit 10 and the readout circuit 12, operations for preparing to read out signals for radiation images from the respective pixels 1 may be started.

[0056] FIG. 5 is a timing diagram showing an example of the operation of the radiation imaging apparatus 100 having the configuration shown in FIGS. 2(a) and 2(b). "Vg1" indicates a signal Vg1 input to the drive line 6a for driving the pixel 1a. "Vg2" indicates a signal Vg2 input to the drive line 6b for driving the pixel 1b. "Vg3" indicates a signal Vg3 input to the drive line 6c for driving the pixel 1c. "Vg4" indicates a signal Vg4 input to the drive line 6d for driving the pixel 1d. Otherwise, it is the same as the configuration shown in FIG. 4 described above.

[0057] Also in the configuration shown in FIGS. 2(a) and 2(b) and the operation shown in FIG. 5, similar to the configuration shown in FIGS. 1(a) and 1(b) and the operation shown in FIG. 4, the detection circuit 13 can obtain irradiation information of radiation from the signal Out with high accuracy. However, the operation shown in FIG. 5 requires four signals Vg1 to Vg4 in order to read out signals from the pixels 1a to 1d once each. Therefore, when performing AEC, the time resolution may be lower when operating in the same clock cycle than in the operation shown in FIG. 4, which requires only two signals Vg1 and Vg2 to read out signals from the pixels 1a to 1d once each. However, since the pixels 1a to 1d can be arranged in different pixel rows, for example, the degree of freedom in setting the region of interest or the like can be increased.

[0058] Also, in the configuration shown in FIG. 2(a), the operation shown in FIG. 4 may be performed. That is, the signal Vg1 may be supplied to the drive line 6a to which the pixel 1a is connected and the drive line 6c to which the pixel 1c is connected at the timing shown in FIG. 4, and the signal Vg2 may be similarly supplied to the drive line 6b to which the pixel 1b is connected and the drive line 6d to which the pixel 1d is connected. This is because in the configuration shown in FIG. 2(a), the pixel 1a and the pixel 1c are connected to different signal lines 3a and 3b, respectively, and the pixel 1b and the pixel 1d are similarly connected to different signal lines 3a and 3b, respectively. Thereby, compared with the operation shown in FIG. 5, the time resolution when performing AEC or the like can be improved.

[0059] When detecting radiation irradiation information separately from the radiation image, the drive circuit 10 drives the pixel 1a and the pixel 1b connected to the common signal line 3a at different timings from each other, and the pixel 1c and the pixel 1d connected to the common signal line 3b at different timings from each other. Further, the drive circuit 10 drives, for example, the pixel 1a and the pixel 1c at the same timing, and also drives the pixel 1b and the pixel 1d at the same timing. Next, the detection circuit 13 detects the irradiation information based on the signals Output1 to Output4 corresponding to the signals output from the respective pixels 1a to 1d. Thereby, while suppressing the circuit scale of the readout circuit 12, it is possible to suppress the influence of offset components and crosstalk caused by elements such as transistors of the readout circuit 12 superimposed on the signals output from the pixels 1a to 1d. Further, as described above, it is possible to suppress the offset components caused by the arrangement positions and drive timings of the pixels 1a and 1b for acquiring information regarding the radiation irradiation amount, and to accurately obtain the radiation irradiation information. As a result, in the radiation imaging apparatus 100, it becomes possible to perform control such as more accurate AEC, and a radiation imaging apparatus 100 that is more user-friendly is realized.

[0060] Hereinafter, a radiation imaging system incorporating the above-described radiation imaging apparatus 100 will be exemplarily described with reference to FIG. 6. X-rays 6060 generated by an X-ray tube 6050, which is a radiation source for irradiating the radiation imaging apparatus 100, pass through the chest 6062 of a patient or subject 6061 and enter the radiation imaging apparatus 100. Information inside the body of the patient or subject 6061 is included in the incident X-rays. In the radiation imaging apparatus 100, a scintillator emits light in response to the incidence of the X-rays 6060, which is photoelectrically converted by the conversion element 20 to obtain electrical information. This information is digitally converted and image-processed by an image processor 6070 as a signal processing unit, and can be observed on a display 6080 as a display unit in the control room.

[0061] In addition, this information can be transferred to a remote location by a transmission processing unit such as a telephone line 6090. As a result, it can be displayed on a display 6081, which is a display unit such as a doctor's room in another location, and a doctor in a remote location can make a diagnosis. Further, this information can be recorded on a recording medium such as an optical disk, or can also be recorded on a film 6110 serving as a recording medium by a film processor 6100.

[0062] The disclosure of this specification includes the following radiation imaging apparatus and radiation imaging system.

[0063] (Item 1) A plurality of pixels arranged to form a plurality of rows and a plurality of columns, A drive circuit that controls the plurality of pixels via a plurality of drive lines extending in the row direction, A radiation imaging apparatus comprising: a detection circuit that detects radiation irradiation information separately from a radiation image based on signals read out from the plurality of pixels via a plurality of signal lines, Each of the plurality of signal lines is connected to pixels arranged in two pixel columns adjacent to each other in the row direction among the plurality of pixels, The plurality of pixels include a first pixel, a second pixel, a third pixel, and a fourth pixel, The first pixel and the second pixel having lower sensitivity to radiation than the first pixel are connected to the same signal line among the plurality of signal lines, and are respectively connected to different drive lines among the plurality of drive lines. The third pixel and the fourth pixel are connected to the same signal line among the plurality of signal lines, and are respectively connected to different drive lines among the plurality of drive lines. When detecting the irradiation information, The drive circuit drives the first pixel and the second pixel at different timings, and drives the third pixel and the fourth pixel at different timings. The detection circuit detects the irradiation information based on information regarding the irradiation amount corresponding to the first signal output from the first pixel and the second signal output from the second pixel, and information regarding the correction amount corresponding to the third signal output from the third pixel and the fourth signal output from the fourth pixel. A radiation imaging apparatus characterized by the above.

[0064] (Item 2) When detecting the irradiation information, the detection circuit Based on the difference between the first signal and the second signal, and the difference between the third signal and the fourth signal, or Based on the difference between the first signal and the third signal, and the difference between the second signal and the fourth signal, the radiation imaging apparatus according to Item 1, characterized by detecting the irradiation information.

[0065] (Item 3) When detecting the irradiation information, the drive circuit drives each of the first pixel, the second pixel, the third pixel, and the fourth pixel such that the time difference between the timing of driving the first pixel and the timing of driving the second pixel is the same as the time difference between the timing of driving the third pixel and the timing of driving the fourth pixel. The radiation imaging apparatus according to Item 1 or 2, characterized by the above.

[0066] (Item 4) When detecting the irradiation information, the driving circuit drives the first pixel and the third pixel at the same timing, and drives the second pixel and the fourth pixel at the same timing. The radiation imaging apparatus according to any one of Items 1 to 3.

[0067] (Item 5) Among the plurality of pixels, two pixels adjacent to each other in the row direction and connected to a common signal line among the plurality of signal lines have a line-symmetric or point-symmetric configuration with the common signal line interposed therebetween. The radiation imaging apparatus according to any one of Items 1 to 4.

[0068] (Item 6) The first pixel, the second pixel, the third pixel, and the fourth pixel are arranged in the same pixel row. The radiation imaging apparatus according to any one of Items 1 to 5.

[0069] (Item 7) The first pixel and the second pixel are arranged in the same pixel column, The third pixel and the fourth pixel are arranged in the same pixel column. The radiation imaging apparatus according to any one of Items 1 to 5.

[0070] (Item 8) The first pixel and the third pixel are connected to a first driving line among the plurality of driving lines, The second pixel and the fourth pixel are connected to a second driving line among the plurality of driving lines. The radiation imaging apparatus according to any one of Items 1 to 7.

[0071] (Item 9) The first pixel, the second pixel, the third pixel, and the fourth pixel are arranged in the same pixel column. The radiation imaging apparatus according to any one of Items 1 to 5.

[0072] (Item 10) The radiation imaging apparatus according to any one of Items 1 to 5, wherein the first pixel, the second pixel, the third pixel, and the fourth pixel are arranged in different pixel rows and different pixel columns from each other.

[0073] (Item 11) The radiation imaging apparatus according to any one of Items 1 to 10, wherein a positional relationship in a row direction and a column direction in which the second pixel is arranged with respect to the first pixel is the same as a positional relationship in a row direction and a column direction in which the fourth pixel is arranged with respect to the third pixel.

[0074] (Item 12) The radiation imaging apparatus according to any one of Items 1 to 11, wherein sensitivities of the third pixel and the fourth pixel to radiation are the same.

[0075] (Item 13) The radiation imaging apparatus according to any one of Items 1 to 12, wherein the first pixel has a higher sensitivity to radiation than the third pixel and the fourth pixel.

[0076] (Item 14) The radiation imaging apparatus according to any one of Items 1 to 13, wherein sensitivities of the second pixel, the third pixel, and the fourth pixel to radiation are the same.

[0077] (Item 15) The radiation imaging apparatus according to any one of Items 1 to 14, wherein the radiation image is generated based on signals output from pixels arranged other than the pixel rows in which the first pixel, the second pixel, the third pixel, and the fourth pixel among the plurality of pixels are arranged.

[0078] (Item 16) A scintillator arranged to cover the plurality of pixels; Light shielding layers respectively arranged between the second pixel and the scintillator, between the third pixel and the scintillator, and between the fourth pixel and the scintillator; The radiation imaging apparatus according to any one of Items 1 to 15, further comprising

[0079] (Item 17) The radiation imaging apparatus according to any one of Items 1 to 16, and a signal processing unit that processes a signal output from the radiation imaging apparatus, A radiation imaging system characterized by comprising

[0080] The invention is not limited to the above embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, the claims are attached to disclose the scope of the invention.

Description of Reference Numerals

[0081] 1: Pixel, 3: Signal line, 6: Driving line, 10: Driving circuit, 13: Detection circuit, 100: Radiation imaging apparatus

Claims

1. A plurality of pixels arranged to form a plurality of rows and a plurality of columns, a driving circuit for controlling the plurality of pixels via a plurality of driving lines extending in a row direction, a radiation imaging apparatus comprising: a detection circuit for detecting radiation irradiation information separately from a radiation image based on signals read out from the plurality of pixels via a plurality of signal lines, wherein each of the plurality of signal lines is connected to pixels arranged in two pixel columns adjacent to each other in the row direction among the plurality of pixels, the plurality of pixels include a first pixel, a second pixel, a third pixel, and a fourth pixel, the first pixel and the second pixel having a lower sensitivity to radiation than the first pixel are connected to the same signal line among the plurality of signal lines and are respectively connected to different driving lines among the plurality of driving lines, the third pixel and the fourth pixel are connected to the same signal line among the plurality of signal lines and are respectively connected to different driving lines among the plurality of driving lines, when detecting the irradiation information, the driving circuit drives the first pixel and the second pixel at different timings, and drives the third pixel and the fourth pixel at different timings, the detection circuit detects the irradiation information based on information regarding an irradiation amount corresponding to a first signal output from the first pixel and a second signal output from the second pixel, and information regarding a correction amount corresponding to a third signal output from the third pixel and a fourth signal output from the fourth pixel. A radiation imaging apparatus characterized by the above.

2. When detecting the irradiation information, the detection circuit detects the irradiation information based on a difference between the first signal and the second signal and a difference between the third signal and the fourth signal, or detects the irradiation information based on a difference between the first signal and the third signal and a difference between the second signal and the fourth signal. The radiation imaging apparatus according to claim 1, characterized by the above.

3. When detecting the irradiation information, the driving circuit drives each of the first pixel, the second pixel, the third pixel, and the fourth pixel such that a time difference between a timing for driving the first pixel and a timing for driving the second pixel is the same as a time difference between a timing for driving the third pixel and a timing for driving the fourth pixel. The radiation imaging apparatus according to claim 1, characterized by the above.

4. When detecting the irradiation information, the driving circuit drives the first pixel and the third pixel at the same timing, and drives the second pixel and the fourth pixel at the same timing. The radiation imaging apparatus according to claim 1, characterized in that.

5. Among the plurality of pixels, two pixels adjacent to each other in the row direction and connected to a common signal line among the plurality of signal lines have a line-symmetric or point-symmetric configuration with respect to the common signal line. The radiation imaging apparatus according to claim 1, characterized in that.

6. The first pixel, the second pixel, the third pixel, and the fourth pixel are arranged in the same pixel row. The radiation imaging apparatus according to claim 1, characterized in that.

7. The first pixel and the second pixel are arranged in the same pixel column, The third pixel and the fourth pixel are arranged in the same pixel column. The radiation imaging apparatus according to claim 1, characterized in that.

8. The first pixel and the third pixel are connected to a first driving line among the plurality of driving lines, The second pixel and the fourth pixel are connected to a second driving line among the plurality of driving lines. The radiation imaging apparatus according to claim 1, characterized in that.

9. The first pixel, the second pixel, the third pixel, and the fourth pixel are arranged in the same pixel column. The radiation imaging apparatus according to claim 1, characterized in that.

10. The first pixel, the second pixel, the third pixel, and the fourth pixel are arranged in different pixel rows and different pixel columns from each other. The radiation imaging apparatus according to claim 1, characterized in that.

11. The positional relationship in the row direction and the column direction in which the second pixel is arranged with respect to the first pixel and the positional relationship in the row direction and the column direction in which the fourth pixel is arranged with respect to the third pixel are the same relationship. The radiation imaging apparatus according to claim 1, characterized in that.

12. The sensitivity of the third pixel and the fourth pixel to radiation is the same. The radiation imaging apparatus according to claim 1, characterized in that.

13. The first pixel has a higher sensitivity to radiation than the third pixel and the fourth pixel. The radiation imaging apparatus according to claim 1, characterized in that.

14. The sensitivity of the second pixel, the third pixel, and the fourth pixel to radiation is the same. The radiation imaging apparatus according to claim 1, characterized in that.

15. The radiation imaging apparatus according to claim 1, wherein the radiation image is generated based on signals output from pixels arranged other than the pixel rows in which the first pixel, the second pixel, the third pixel, and the fourth pixel among the plurality of pixels are arranged.

16. a scintillator arranged to cover the plurality of pixels; light-shielding layers respectively arranged between the second pixel and the scintillator, between the third pixel and the scintillator, and between the fourth pixel and the scintillator; The radiation imaging apparatus according to claim 1, further comprising the above.

17. A radiation imaging apparatus according to any one of claims 1 to 16; a signal processing unit that processes a signal output from the radiation imaging apparatus; A radiation imaging system, characterized by comprising the above.

Images